Wad



l der, shot, and a closure foi` the tube.

Patented June 5, 1945 WAD Walter L. Finlay, Bridgeport, Conn., assignorto Remington Arms Company, Inc., a corporation of Delaware ApplicationJune 26, 1941, Serial No. 399,849

3 Claims.

This invention relates to aA lubricant which must remain7 in placeundervarying conditions,

and to which extraneous objects will not stick; and in particularrelates toa lubricant suitable for use on shot shell wads and otherammunition components. The description that follows will be directedparticularly to shot shell wads, butv it is to be distinctly understoodthat a lubricant made in accordance with this invention may be usedgenerally and also for other ammunition components.

Conventionally, a shot shell includes a head of metal and a bodycomposed of a paper tube which contains the powder, wads over the pow-There are other components which need not be mentioned at the presentmoment. The wad or wads located between the powder and the shot. may bereferred to as the shot shell filler Wad or wads. Usually there is aplurality of wads between the shot and the powder, although for thepurpose of this invention the number is immaterial. Among the purposesof the filler wad may be enumerated:

(1) Sealing of the hot powder gases from the shot;

(2) Provision of a lubricating oily lm on the bore of the barrel toseparate the lead pellets from the steel bore and thus prevent leading;and

(3) Separation of the shot from the powder.

One of the important requirements of the wad is that it not combinephysically or chemically with any of the other elements of the shotshell.

The wads are lubricated at the edges, but inevitably some of thelubricant will nd its way upon the faces of the Wad. It is obvious thatby having the lubricant on the edge of the wads that it will betransferred to the barrel as the Wad passes therethrough. It has been'found that the sharp impact of the wad upon the shot a5 the shell is redwill drive the wad into the shot pellets. vIf the lubricant is sticky orhas a high tensile strength, a considerable portion of the shot willremain attached to the wad after it `leaves the gun. This means thatpart of the shot has lost its usefulness land that the ller wad ybecomesa hazard. One of the objects of the invention is to provide a lubricantfor the filler wad which will not cause thev shot to stick thereto andwhich, at the same time, will not run under conditions of hightemperature and spoil the powder charge. Other objects of the inv'entionwill appear from the description.

In the drawing:

Fig. 1 is an elevation, partly in section, of a conventional shot shellshowing the relation of the shot pellets and shot shell ller wads to theother components 'of the shot shell.

Fig. 2 is a, fragmentary view of the ller wad vdirectly underneath theshot shell pellets showsuch as when subjected to elevated temperatures,

ing the manner in which the pellets are indented into the wad as theshell is red.

Referring now paticularly to Fig. 1, I0 is the powder, l I the head,usually of metal, I2 the base wad, I4 the shot shellpellets, usuallycomposed of lead or an alloy thereof, and I5 the conventional primer.The ller wads are indicated at I3 and I3'. Filler wads I3 may be ofpunched felt or any of the usual materials, such as that disclosed forexample in the patent to Woodford, No. 2,026,765. I3 may be of cardboardor similar material. lWhen the gun is red the primer is first set off,which in turn ignites the powder I0 and starts the movement of the wadsI3 and` I3 With the pellets I4 out of the shell and through the barrelof the gun. The paper tube I1 of the shot shell may have any type ofdesired closure at the end I8, such as a paper wad, or may have the endsof the tube turned inwardly to form a closure. As the wads I3 leave thepaper tube they will expand to the diameter of the boreof the gun. Dueto the sudden movement of the wads I3 and the inertia of the shot shellpellets I4, the pellets lying next to the Wad will be indented therein,such as shown at IB in Fig. 2. The bers of the wad I3 will tend toengage the surfaces of the shot shell pellets I4.

such a missile is dangerous as Well as a detriment to the shot pattern.It has been the practice previously to use rened paraffin waxes andcrude scale paraflin wax as a Wad lubricant. Refined paraffin waxes arelow in their oily constituents and, as a result, are hard and give acomparatively incompressible edge to the filler wad. When the wad isforced into position in the shell, an undesirable bulging of the shellmay occur because the wad is purposely made oversize so as to givebetter sealing qualities. Crude scale wax contains a certain percentageof low melting oil constituents, and because of the low melting pointsof the oily constituents, the wads are not satisfactory after storage atelevated temperatures, for ,example to 120 F. These temperatures arefrequently exceeded for long periods when in storage, such as when 'inthe usual corrugated iron warehouse or in the holds of freighters inwarm climates. The low melting constituents liquefy and run into thepowder with the result that the pressure and velocity obtained upon ringof the shell are so affected that squib loads frequently occur. Varioussubstances have been used to modify the crude scale wax, such as,- forexample', an amorphous orV microcrystalline petrolatum wax. 'Iheaddition of the amorphous or microcrystalline petrolatum wax reduces therunning, but the shot sticks to the wad upon ring. A test was run todetermine the amount of shot sticking with various combinations ofparain and crude scale wax, as indicated in the following table:

It is to be noted that 100 out of 100 wads `fired lubricated with 80%crude scale 20% Vmicrocrystalline wax had shot pellets stick thereto.When the wads were lubricated with 100% 135 F. paraffin wax, 94 out of100 wads-fired had shot pellets sticking thereto'. It was then thoughtthat if an oil were added to the combination that the tensile strengthof the refined parain might be reduced to such an extent that the shotwould not stick to the wad.V

The so-called tensile strength" of a wax is apparently a function of thecrystalline structure and oil content. Many paraffin waxes have aplate-like structure and the oil in the wax tends to collect between theplate-like crystals, thus forming weak planes of cleavage. It followstherefore that a large percentage of oil will reduce the tensilestrength.

Referring to Fig. 2, the shot pellets are impressed into the wad as itis fired and, if the tensile strength of the wax is high enough, the

pellets will not break away therefrom and particularly because of thefact that the fibers of the wad tend to hold the shot 'pellets in placein conJunction with the high tensile strength Wax.

The fibers of the wad grasp the body of the pellet,

and if the Wax is of a high tensile strength, it will be apparent thatthe pellet will not be disengaged therefrom with ease. If the lubricanthas a low tensile strength the bers will more readily give and allow thepellet to be disengaged from the wad.

A combination of 99.75% 135 F. parailinwax and .25% oil was tried, andit was found that -92 out of 100 wads red still had shot stickingthereto. It is evident, therefore, that none of these lubricants weresatisfactory as far as shot sticking is concerned.

It was then suggested that an unlubricated Wad be placed directly underthe shot, but even though no shot sticking occurred, there was 'aconsiderable lowering in pressure, velocity and holes therein. Shotsticking to a wad will detract from this pattern, and the Wad itselfinstead of falling away will continue, due to its increased weight, andmay seriously aii'ect the results.

In the ksearch for a means of reducing shot sticking, oleostearine wastried and, in accordance with Table II, none of the 100 wads fired had,any shot .sticking thereto. Diiicultyhowever, was experienced in therunning of the lubricant into the powder, so it was thought that the Vuse of a microcrystalline petrolatum wax might prevent such running andyet not cause shot sticking. However, as shown in Table II, such was notthe case, and a .951% oleostearine, 5% microcrystalline petrolatum waxlubricant had 33% of the wads fired with shot sticking thereto.

A combination of oleostearine and what is believed to be a hydrogenatedanimal fat, sold on the market as Armour Product #1, were combined inthe proportions of oleostearine and 20% hydrogenated animal fat; and thesurprising result was reached that none of the 98 wads found out of the100 red had shot pellets sticking thereto, as shown in Table III.

Table III Qleostearine-hydrogenated an- Oleosteariue percent-H. A. F.mm1 fat Armour product #l percent Wads having shot sticking l 0 0 29Weds found out of 100 firedi 98 98 06 Likewise, with a 60% oleostearineand 40% hydrogenated animal fat combination, none of the 98 wads out ofthe 100 red had shot pellets sticking thereto. However, when thehydrogenated animal fat was used by itself as a lubricant, 29 out of 96pellets found out of 100 fired had shot sticking to the Wad. I'his showsthat forv some reason the combination of oleostearine and hydrogenatedanimal fat gave'a wad lubricant which prevented the shot from sticking.

The next question that arose was that as to whether or not such acombination would run under elevated temperature storage and therebyadversely aiect the powder. The best practical test for determiningthe-running of a lubricant is to load the wads into shells'and 4storethe shells for a period of time at an elevated temperature. Such a testis lengthy and costly, and it has been found that a good index of therunning characteristic of, the lubricant may be obtained by the vuse ofa so-called running number. The running number is :obtained by placing asmall disc of the material of about 1.45 cm. diameter on a lter paperof/9 cm. diameter, and placing the paper in an oven at 120 F. for agiven period of time. If there is rio-running there -will ybe noindication of a grease spot formed on the lter paper. If, however, thereis running, a grease spot will appear, and the longest diameter of thegrease spot and the diameter at right angles thereto are measured andthe product thereof taken as the running' number. Such a running testwas made for a crude scale and microcrystalline petrolatum waxcombination and for a crude scale and hydrogenated animal fatcombination, with the results shown in Table IV.-

Table IV Crude scale wax-hydrogenated Crude scale wax-microcrystalanimalfat (Armour product #1) line petr. wax

Run- Run- C. S. W. M. P. W. ning C. S. W. H. A. F. ning No. No.

It is to be noted that the hydrogenated animal fat increased the runningof the crude scale wax to such a point that it entirely covered the lterpaper, which obviously would not give a satisfactory lubricant. The useof the hydrogenated animal fat, however, with stearine improves therunning properties very appreciably, and particularly at elevatedtemperatures above that which is normally considered necessary forammunition.

The following Table V shows the results of storage at varyingtemperatures of shot shells for two weeks at room temperatures, 115,120, 125 and 130 F. The average pressures and velocities were obtainedfor shot shells with wads lubricated entirely with oleostearine and forwads lubricated with an 80% oleostearine and 20% hydrogenated animal fatlubricant. It is to'be noted that at 120 F. storage, the shot shellshaving wads lubricated with 100% stearine were not satisfactory inasmuchas many of them had such low pressures and velocities that they did notrecord, as noted in the table. At 125 F., the 80% oleostearine. 20%hydrogenated animal fat lubricated wad shells were still satisfactory,and inasmuch as 120 F. storage is the usual test, it indicates that awad so lubricated can withstand the 125 F. test, giving it a margin ofsafety.

1 Many of shells stored at this temperature had'suchlow pressures andvelocities that their pressures and velocltles did no t record minimumpressure which will record, 3,000; minimum velocity 600) running agent,although there are some shot sticks. It is not quite as good vas thehydrogenated animal fat although it will perform satisfactorily. It hasbeen found that a vegetable oil which gives mostly the glycerides ofpalmitic and stearic acid upon hydrogenation exhibits the desiredproperties. Tallow is made mostly of the glycerides of palmitic, stearicand oleic acids. oleostearine is usually made by pressing out of tallowall of the liquid glycerides possible (mostly glyceryl oleate), thusleaving behind largely a mixture of the glycerides of palmitic andstearic acids. All of the liquid glycerides, of course, are not removedby pressing, so that some small quantities must remain in the iinishedoleostearine. In the hydrogenation of the animal fat it may be thatchemically the result is generally similar to oleostearine, althoughthis is not precisely known. However, the behavior of the oleostearineand the hydrogenated animal fat and combinations thereof are not thesame, and applicant has discovered that such a combination ofoleostearine and a hydrogenated fat produces a satisfactory wadlubricant to which shot will not stick and which does not give excessiverunning, thereby giving satisfactory results in shot shells.

The physical characteristics of a hydrogenated animal fat which issatisfactory may be as follows:

n addition to the use merely as a lubricant, the composition of thisinvention may also serve as a binder for certain types of wads such as,for example, a roong felt wad. Insuch a case,

the wad would be impregnated substantially' completely with thelubricant. It is to be distinctly understood therefore that the wordlubricant where used in the claims, also includes its use as a binder ora means to increase y the impermeability of the wad to passage of gastherethrough.

By this invention a lubricant which will not run and to which extraneousobjects will not stick. Many modiiications may be made and the specificcompositions are merely by Way of example so that the scope of theinvention is not intended to be limited except as defined by theappended claims.

What is claimed is:

1. A shot shell wad having a lubricant impregnating the surface of saidwad, said lubricant rendering said wad substantially non-shot stickingand being substantially non-running, and composed substantially ofoleostearine and 20% of a hydrogenated animal fat, said fat beingsubstantially solid and having a melting point greater than F.

2. A shot shell wad having a lubricant impregnating the surface of saidwad, said lubricant rendering said wad substantially non-shot stickingand being substantially non-running, and composed of oleostearine andbetween aD- has been found proximately 20% to 40% of a hydrogenatedanimalA fat, said fat being substantially solid and having a meltingpoint greater than 120 F.

3. A shot' shell Wad having a lubricant impregnating the surface of saidWad, said lubri-y cant rendering said Wad substantially nonshot stickingand being substantially non-running,

said lubricant being composed of between approximately 20% and up to 40%glycerides of hydrogenated fatty acids, said glycerides of thehydrogenated fatty acids being substantially solid and having a meltingpoint greater than 120 F., and glycerides of natural fatty acids.

WALTER L. FINLAY.

